Submillimeter-Scale Zero-Dimensional Cs₄PbBr₆ Perovskite Rods: Fabrication, Optical Properties, and Applications

An antisolvent approach is developed to fabricate phase-pure zero-dimensional (0-D) perovskite Cs4PbBr6 microrods at submillimeter length scales with the microrod length facilely controllable by the growth time. A strong greenish photoluminescence narrow band is observed in the developed Cs4PbBr6 microrods. The corresponding photoluminescence quantum yield is as high as ∼50%, which is the highest value among microscale or bulk phase-pure Cs4PbBr6 materials reported thus far. When an individual Cs4PbBr6 microrod is pumped with a picosecond laser, the photoluminescence spectrum exhibits significant spectral narrowing down to 1 nm, suggesting the occurrence of lasing resonance. The pump threshold and lasing efficiency show strong dependence on the polarization of the pump laser with respect to the longitudinal axis of the microrod, offering a robust approach to tune figures of merit of lasing resonance. Moreover, lasing resonance strongly depends on the microrod length and longer microrods intend to emit stronger signals with obviously suppressed saturation behavior. Speckle-free optical imaging is demonstrated using an individual 0-D perovskite microrod laser to illuminate microscale objects, suggesting fundamental interest and potential applications of 0-D perovskite anisotropic structures.